It is considered that a solid-state battery in which an electrolyte is comprised of a solid electrolyte is capable of simplifying a safety device and is excellent in production cost and productivity, since it does not use a flammable organic solvent in the battery. In particular, in recent years, with the increase in demand for a hybrid vehicle, electric vehicle, etc., there is a need to improve the capacity and output as well as safety of solid-state batteries. Patent Literature 1 suggests a method for producing a solid-state battery comprising a step of preparing a stack by stacking in order of a positive electrode current collector, a positive electrode layer, an electrolyte layer, a negative electrode layer, and a negative electrode current collector, and subsequently restraining the stack while pressing the stack in the stacking direction, in order to prevent the delamination between the current collectors and the positive or negative electrode layer. In addition, Patent Literature 2 suggests adjusting the pressure applied to a power generation element (unit cell) comprising a positive electrode, a negative electrode, and an electrolyte disposed between the positive and negative electrodes, by the fluid filled within a sealed vessel accommodating the power generation element. Moreover, Patent Literature 3 suggests a vehicle driving unit comprising a drive control means for controlling the discharge current of a battery by adjusting the pressure applied to the battery with a pressure adjusting unit depending on the vehicle driving state.
As described above, it has been suggested to press a stack of a positive electrode layer, an electrolyte layer and a negative electrode layer during the production or use (during vehicle driving) of a battery. However, during the production of an assembled battery in which a plurality of the solid-state batteries comprising such a cell are stacked or during use of such solid-state batteries or assembled battery, there is a possibility of a malfunction such as destruction, excessive output, etc., of the battery, if the stack or solid-state batteries is or are pressed excessively due to the failure of the control system of the production apparatus or pressure control device.